In conventional ordinary ink jet printers, a printing head provided therein is moved in a lateral direction (main scanning direction) with respect to a printing article such as paper, while the printing article is fed in a longitudinal direction (sub-scanning direction), so that printing is performed. In this event, ink droplets are discharged toward the printing article from a plurality of ink nozzles of the printing head as required for the printing. On the other hand, when a printing operation is not performed, the printing head is positioned away from a printing operation range and faces a head cap since the ink nozzles are otherwise susceptible to clogging due to dried ink existing therein and to attachment of dust.
The head cap serves to seal the leading end of the printing head and suck ink droplets from the ink nozzles (i.e., clean the printing head). In addition, the head cap forces all of the ink nozzles of the printing head to discharge ink droplets prior to the start of a printing operation. Further, when printing is stopped for a few seconds during a printing operation, the printing head is also faced with the head cap such that all of the ink nozzles of the printing head are forced to discharge ink droplets (flushing) in order to prevent the ink nozzles from clogging due to dried ink.
Wasted ink thus sucked or discharged from the printing head is introduced from the head cap into a wasted ink tank (wasted ink recovery unit) by a wasted ink pump and stored therein. While the wasted ink tank is removably mounted in an ink jet printer such that wasted ink is removed therefrom when the wasted ink tank is filled with wasted ink, the capacity of an ordinary wasted ink tank is not designed on the assumption that the stored ink is removed, but on the basis of years of endurance of the ink jet printer (approximately 300 cc-500 cc).
A printer including an ink cartridge having a wasted ink tank integrated therewith is also known (for example, Japanese Laid-open Patent Applications Nos. 2-192953 and 4-364960). The disclosed printer has a wasted ink tank (having a capacity of several tens of cubic centimeters) defined in a portion of an ink cartridge (directly coupled to a printing head) for supplying the printing head with ink, so that wasted ink can be removed together with the ink cartridge when it is exchanged with new one.
In the conventional ink jet printer as mentioned above, the space for the wasted ink recovery unit (wasted ink tank) causes a large obstacle to a reduction in size of the ink jet printer. Specifically, since a wasted ink tank designed on the basis of years of endurance stores an amount of wasted ink in accordance with the years of endurance, a relatively large space is required therefor in an ink jet printer. A wasted ink tank included in an ink cartridge also requires a large space therefor because of movements of the wasted ink tank together with the ink cartridge, even if the capacity of the wasted ink cartridge itself is small.
Furthermore, since a conventional flushing operation requires a printing head to be moved to the position of a head cap during a printing operation, this causes a large loss of time, thus preventing a reduction in printing time.
It is therefore an object of the present invention to provide a cartridge for an ink jet printer which is capable of directly or indirectly reducing the capacity of a wasted ink recovery unit without any restraint to a printing function, an ink jet printer which is adapted to accommodate this cartridge, and an ink jet printer which is capable of reducing a printing time.